The semiconductor industry has experienced rapid growth due to continuous improvements in the integration density of various electronic components (i.e., transistors, diodes, resistors, capacitors, etc.). For the most part, this improvement in integration density has come from repeated reductions in minimum feature size, which allows more of the smaller components to be integrated into a given area. These smaller electronic components also require smaller packages that utilize less area than previous packages. Some smaller types of packages for semiconductor components include quad flat packages (QFPs), pin grid array (PGA) packages, ball grid array (BGA) packages, and so on.
Currently, integrated fan-out packages are becoming increasingly popular for their compactness. In the integrated fan-out packages including multiple chips that are encapsulated by the molding compound, reliability of electrical connection between the chips and the redistribution circuit structure fabricated on the molding compound may deteriorate due to thickness difference between the chips. How to increase yield rate of the fabrication of integrated fan-out packages is highly concerned.